2014 YZ450F Shut off problem

Hello, I read this forum all the time and wonder if I could get an answer to a question I have.


I have a 2014 YZ450F and I put a FMF Factory 4.1 slip on exhaust on it. I did a 2 hour woods race this weekend and it stalled on me 3 times during the race. I sat their kicking it for about 10 minutes. Sometimes when I was racing down the trail it would make a crackle/pop noise. I think it might have something to do with the mapping, but not sure. The stalling was not from the clutch and locking up the brakes, it just would cut out sometimes. Then it wouldn't start and I would have to kick it so many times. If anyone has any answer that would help, thanks. The mapping I have right now is just all 0s, just the stock mapping. 


Deff sounds like mapping mine was extremely lean from factory id say richen her up and u will be fine

Ok I will try to richen it up and see how it does. Thanks

I agree sounds like mapping. Mine was hard to start stock before the mapping change.  Not sure bout mapping for just the slip on, stock exhaust go with the MXA Preston Map, and with the full FMF system I only increased the Fuel as per the numbers also in MXA. Might need to experiment a little.

Crackling/popping while under power, or decel?

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